ISTANBUL — Hundreds of police in riot gear pushed past improvised barricades early today to reach Istanbul’s central Taksim Square, firing tear gas and rubber bullets to scatter protesters who have occupied the area for more than a week.

Many of the demonstrators fled into the square’s Gezi Park, where hundreds have been camping as part of the occupation aimed at stopping a development project in the park. Bulldozers immediately began dismantling some of the barricades and makeshift shelters set up on the square, although they insisted they would not move into the park.

The police clampdown on Taksim Square came on the 12th day of nationwide protests which grew from a peaceful demonstration against a redevelopment of Gezi Park into a test of the authority of Prime Minister Recep Tayyip Erdogan. The unrest was inspired in part by some seeing his increasingly authoritarian style of governing and his perceived attempts to impose a religious and conservative lifestyle in the country with secular laws.

Erdogan, a devout Muslim, says he is committed to Turkey’s secular laws and denies charges of autocracy.

Three people have died — two protesters and a policeman — and more than 5,000 have been treated for injuries or the effects of gas during the protests. The government says 600 police officers have also been injured.

Throughout the protests, Erdogan has struck a defiant tone, vowing to press ahead with the Taksim redevelopment plans, dismissing the protesters as fringe extremists and the protests as undemocratic plots to topple his government, which was elected with 50 percent support in 2011.

He has called major pro-government rallies in Ankara and Istanbul this weekend to show that he too can get large numbers of his supporters out on the street.

The government announced late Monday that Erdogan would meet with some of the Gezi Park protesters on Wednesday, but that authorities would not allow “illegal” demonstrations to continue.

Speaking Tuesday, Erdogan maintained his position that the protests were part of a conspiracy against the government.

“They are trying to prevent Turkey’s rise. (The protesters) are being used by some financial institutions, the interest rate lobby and media groups to (harm) Turkey’s economy and (scare away) investments.” He added: “I want everyone there to see the big picture, to understand the game that is being played and I especially invite them to evacuate (Taksim and Gezi Park). I expect that of them as their prime minister.”

In Taksim, police addressed the protesters through loudspeakers, insisting they had no intention of moving into the park, but needed to clear the square and take down protest banners. They appealed for calm, saying they did not want to use tear gas.

But in his speech, Erdogan implied the park would not be allowed to be occupied for long.

“I am sorry but Gezi Park is for taking promenades, not for occupation,” he said, referring to the meaning of the word Gezi, which translates as promenade.

Clashes broke out on the edge of the square between riot police and small groups of protesters throwing fireworks, firebombs and stones at the police water cannon trucks, with authorities responding with tear gas and jets of water. The vast majority of protesters, most of who remained in the park, were peaceful.

Unsuspecting commuters emerging from the square’s metro station ran for cover, aided through the clouds of acrid chemicals by protesters offering them antacid solution in spray bottles to help protect them from the worst of the sting.

At least one protester was injured or overcome by gas, and was rushed on an improvised stretcher by others to a medical station set up by protesters in the park. It was unclear how serious his condition was.

A police vehicle was set alight by a firebomb, and a water cannon truck was used to extinguish the blaze.

Istanbul Gov. Huseyin Avni Mutlu said the police operation aimed to remove the posters and banners hanging at Taksim, some of which belonged to outlawed groups, that were damaging Istanbul’s international image.

He said clashes erupted with “marginal groups” that had thrown fireworks and firebombs and had set one police vehicle alight, and he reassured people holding peaceful protests at Gezi Park that they would not be touched.

“I would like to say one more time that there is no question of any (police) intervention at Gezi Park,” he said, and accused those clashing with police of trying to provoke wider clashes at Taksim.

“We are maintaining our self-control. (Police) shall remain around these places to prevent (protesters) from climbing on them and surrounding them with their materials,” he said.

Mutlu said a number of demonstrators were detained. He said there were no injuries during the police operation, but that some people had suffered small cuts and bruises.

But protesters were skeptical of the promise.

“Of course nobody believes the police or the governor when he says police will not interrupt the gathering in Gezi Park,” said Tarsu Orzyurt. “We won’t believe them anymore. We saw policemen telling us, ‘Come to the street and don’t be afraid,’ then they shoot at us (with tear gas). So nobody believes them.”

Demonstrators had manned the barricades and prepared for a possible intervention when they saw police massing in the area shortly after dawn this morning. But in the end, the police moved easily through the barriers, initially arriving on Taksim through a small, lightly protected side street.